| Show 1 KILL JILL ALFALFA WEEVIL WITH POISON SPRAY v WASHINGTON ASHINGTON D D. D C. C Farmers C.-Farmers Farmers in regions newly infested by the alfalfa weevil will wUl be interested In knowing that an unusually effective method of or control has been worked out bythe bythe by bythe the United States Department of A Ag Ag- Specialists of or the department department depart depart- ment hunt say that rarely has any method of insect control been so thoroughly safeguarded against failure as alfalfa weevil Jt spraying It has bas been tested every ver season for seven years The cost of the operation operation about about 1 an as with the Is acre js trifling compared returns and no farmer in the territory territory territory terri terri- tory infested or threatened can afford af af- aCford afford ford to overlook it the specialists say There Is no control me measure however which can be applied ad advantageously al- al this late In the season Effective work must be delayed until next spring Control is effected by spraying poison over the fields so that it will wil cover er the growing parts on which the weevils mostly feed Arsenate of lead and of zinc have been mostly used but other recommended recommended recommended re re- re- re commended for Cor orchard spraying are thought to be about as good There Is practically no danger clanger of burning the foliage e of alfalfa and therefore the range rang of or suitable poisons is larger than in fruit tree spraying Arsenate of load is said to be everything considered considered considered con con- the best poison polson to use u e principally prin prin- principally because it sticks to th the leaves more readily and costs less than most of the others The poison polson Js is weighed or measured at the rate of two pounds of ot powder or 01 four pounds of commercial paste for each gallons of water is stirred with a little water In a pall pail until It becomes a thin paste without lumps is diluted and strained into the sprayer tank Two pounds of at laundry soap Boap for tor each gallon should be added In order to make the liquid stick to the leaves leans properly The dry powdered form of poison polson Is better than the paste There Is no danger of stock being poisoned by hay cut from sprayed fields where the poison polson Is applied at a rate not greater than gallons of spray mixture per acre cre Simple Outfit Sufficient The essentials of the spraying outfit outfit out fit are A truck or other vehicle a tank with an agitator to keep th the e poison polson from settling to the bottom a pump a pressure gauge an engine and pumping jack unless the pump is to be driven by hand a strainer a pipe for distributing the liquid from the pump and as many nozzles as are required b by the capacity of the pump These essentials may all be contained In a pump barrel-pump outfit carried in a wagon The pump must be capable of ot delivering four-fifths four of a gallon or more a minute and maintaining a n pressure of at least 75 pounds If It the pressure is less than that the mist spray pray will not be fine enough to prevent the liquid from gathering in drops and running to the ground instead bf of drying on the tops tapa of the plants The number of nozzles used should be sufficient to take up the capacity of or the pump At the average walkIng walkIng walk- walk Ing lug gait galt of a team each nozzle should deliver tenths nine-tenths of a gallon a mi mi- nute Therefore a pump of nine- nine i gallon capacity per minute will supply supply supply sup sup- ply ten nozzles each of or which covers a strip two feet teet wide By an arithmetical arithmetical arithmetical arith arith- calculation of the cubical content content content con con- tent of the pump cylinder and the number of strokes per minute the capacity of the outfit can be deter deter- mined The spray should be applied at the rate of gallons of spray mixture per acre Nearly any kind of or spraying outfit can can be adapted for this purpose However modern orchard spray outfits outfits out out- fits fits are are usually designed to give a comparatively small flow and high pressure and are less suitable for alfalfa alfalfa alfalfa al al- al- al falfa spraying than the Ider pumps with larger cylinders and longer stroke designed for larger flow and lower pressure Keep Liquid Well Stirred The spraying outfit should be mounted on the wagon or other vehicle vehicle vehicle ve ve- hicle used so that the nozzles will be beabout beabout beabout about two feet teet above the tops of at the alfalfa plants Four gallon 50 barrels barrels barrels bar bar- with an engine and pump mounted mounted mounted moun moun- ted on an ordinary wagon or for a hand pump outfit an express wagon and fewer barrels constitute a satisfactory satisfactory satisfactory satis satis- factory outfit A paddle dasher or orsome orsome orsome some other form of agitator must be provided to keep the liquid stirred A strainer of mesh 20 brass or bronze screen should be fitted to the opening through which the water enters the tank and another over the outlet leading to the pump The parts of the pump in which close fitting is required required required re re- should be of ot brass bronze porcelain or some other substance less rapidly corroded by the chemicals chemicals chemicals chemi chemi- cals than are Iron and steel All commercial spray pumps are built inthis In Inthis this way but pumps which were intended Intended intended In in- tended for other purposes should be refitted when used for spraying An engine-driven engine outfit must have havea a relief valve near the pump permitting permitting permitting permit permit- ting the surplus flow to return to the tank The pump must have an air pressure chamber large enough to keep the flow steady and Insure even distribution of the poison polson Even pressure indispensable for uniform spread of at the poison cannot be maintained maintained maintained main main- without a pressure gauge This gauge should hould be attached to the pressure pressure pressure pres pres- sure chamber or near It and at a distance distance distance dis dis- tance from the relief valve and the nozzles The boom or pipe which carries the nozzles and supplies them with liquid from tram the pump Is made of 2 foot 2 foot pieces of 14 inch Iron pipe Joined by Ts T's each of which affords an opening for the attachment of a nozzle The boom Is connected with the pump by a inch inch pressure hose hOBe The boom should be supported by a apiece apiece apiece piece of timber 2 by 2 clamped or hinged to the truck with the boom stapled bolted or wired to It Plain misty nozzles without strainers or other complications should be used Spray In Warm Weather The best time for spraying Is at what the tho specialists call the turning point of at weevil Infestation infestation from from one to two weeks before the first crop cropIs Is ready rendy for cutting when the young larvae become so numerous that they thoy completely destroy the growing tips After that point Is reached the weevils weevils wee wee- vils If It left alone consume the leaves until nothing Is ta left but the woody wood fibers If It spraying Is done at this time Lime the crop recovers quickly Spraying yearly in the spring sometimes some- some times imes entirely prevents damage but it is uncertain On the other hand plants sprayed after atter they were entirely en- en Irely stripped of their foliage have been een able to recover and bloom but this allows destruction to go too far tar farand farand and makes recovery recover too slow Spraying at the turning point not lot only protects the first crop but confers an even larger benefit on the second crop which sprouts and grows without delay and no treatment of or the stubble is necessary Stubble spraying after atter the cutting of the first crop has been successfully successfully success success- fully done but hut It requires S getting into Int W the the-tf the field ld- ld i immediately t l after tt r- r cutting cutting cut cut- i 1 ting and a much larger quantity of liquid Is required than If It It were apI applied applied ap ap- ap- ap I plied pIled to the first cro crop Stubble spraying spraying spraying spray spray- ing therefore is advised only when earlier spraying has bas been impossible Spraying should be done if possible possible possible ble at the beginning of a warm spell The weevils do not feed so voraciously voracious voracious- ly In cool weather and if It the poison polson is applied at the beginning of a cool spell it may become largely Impotent before the weevils resume feeding freely When spraying is done under under under un un- der favorable weather conditions most of the weevils are killed within four or five days There are other measures but none of them promises much unless unless unless unless' un un- un- un less less' applied before or immediately after atter the first cutting One method is to pasture the alfalfa field until most of the eggs and young larvae have been destroyed Another Is to use the alfalfa as a soiling crop cutting cutting cutting cut cut- ting It green two or three times Umes durIng during during dur dur- ing the season These methods however however however how how- ever must be practiced before the turning point of infestation as after atter that time the weevils destroy the plants so BO completely that there Is not enough growth for tor either pasture or soiling Another method Is to cultivate cultivate cultivate vate the field with a harrow harrow- or other implement Immediately after atter the first cutting in such wa way as to cover the field with a dust mulch thus exposing exposing exposing ex ex- ex- ex posing the entire surface of the field eld to the sun and killing most of at the weevils In some Instances the second second second sec sec- ond crop has been protected by dragging dragging dragging drag drag- ging the stubble while it is still wet from with irrigation the land leveler or the clod breaker This causes the Insects to perish by embedding them in the mud but it is harmful to the soil soU and is not recommended |
